Coated abrasives made from dimensionally stable woven polyester fabric have recently come into commercial use. In heavy duty applications of such belts, particularly when made from the coarser grits of the new co-fused alumina-zirconia abrasives, one mode of failure of the product occurs because of grain shedding from excessive cracking of the maker coat due to flexing in use. Another mode of failure in such belts is mechanical rupture of the belt joints. The backing member of the present invention provides for the manufacture of improved lap type joints for forming endless abrasive belts.
While it is conventional in the coated abrasive art to apply a flexible backsize such as rubber modified backsize to the fabric to stiffen it, the present invention provides a modified backsize imparting improved properties to the coated abrasive product relative to grain retention and joint manufacture.